The present invention relates to an automatic apparatus for stacking signatures which are discharged from a rotary printing press. More particularly, it is concerned with an automatic apparatus for stacking small bundles of signatures, wherein the signatures are piled up evenly in a small bundle, then this small bundle is rotated 180 degrees and stacked one by one alternately for stack compensation to form a large bundle of such signatures.
As this type of the device, there has so far been known such an apparatus as disclosed in Japanese Unexamined Patent Publication No. 189965/1982. The conventional apparatuses including the one disclosed in the referenced publication, however, are composed separately of a section for piling up signatures into a small bundle, a rotary section to change the direction of the bundles alternately, and a section for stacking these small bundles. Moreover, each section is provided at a different location with the result that the entire structure of the apparatus becomes inevitably large in size. In the following, explanations will be given as to the embodiment disclosed in the referenced Japanese Unexamined Patent Publication No. 189965/1982.
As shown in FIG. 8 of the accompanying drawing, the conventional automatic bundle stacking apparatus is composed of a piler B, a rotary section C, and a stacker section D, each being at a separate position. A reference letter A designates a paced signature conveyor, and a reference letter a denotes a sorting device. The signatures E which have been conveyed in condition that they are partially overlapped in a stream are further carried forward while they are being clamped between conveyor belts F and G. As soon as the signatures hit a stopper H, they drop one by one in a horizontal posture onto a receiving table U and pile up thereon gradually. In the meantime, the receiving table U lowers its position in order to maintain the uppermost surface of the piled signatures E at a substantially constant level. As soon as a predetermined amount of the signatures for a bundle has been reached, the sorting device a is actuated and the receiving table U is rapidly lowered to place a pile P of the signatures on a conveyor Y. Then, it returns to the original position. While the receiving table U performs such rapid vertical motion, the stream of signatures E is temporarily stopped by a fork I which is able to travel both horizontally and vertically. A cylinder X, a pinion L, and a pinion rack K constitute a mechanism for moving the table U horizontally and vertically. When the small bundle P of the signatures E on the conveyor Y hits a stopper J and terminates its forward movement, a table O is raised by means of a cylinder W, and, after performance of a required rotational movement by means of a pinion M and a pinion rack N, it is lowered. The small pile P of the signatures E is again sent forward by a conveyor Y'. As soon as it hits a stopper Z and terminates its movement, a table Q is elevated by means of a pinion R and a pinion rack S. When the uppermost surface of the small bundle P of the signatures E comes into contact with the lower surface of a large bundle supporting fork V, the fork V is opened as indicated by double-dot-and-dash lines V', and the table Q is further elevated upward until its top surface reaches a position slightly above the top surface of the supporting fork V and is stopped there. Then, the supporting fork V is closed and the table Q begins to descend. Then, if one or more small bundles P have already been stacked on the supporting fork V, the bundle now coming in by the ascending table Q will be placed above the bundles previously stacked. In this manner, the stacking is repeated. When the predetermined numbers of the small bundles P have been stacked with the lowest bundle being positioned by the ascending table Q to be slightly above the top surface of the supporting fork V, a carrier T with its forks being open begins to close its fork. Then, the table Q is again descended. The stacked bundles P are now held by the forks of the carrier T and are transferred to the next station in the work.
As has been explained, in the conventional apparatus, the section for piling up signatures into a small bundle, the section for turning it 180.degree. alternately, and the section for stacking the small bundles to form a large bundle are separately positioned. Therefore, the entire structure of the apparatus inevitably becomes large so as to require a larger floor space for its installation.